Emerging therapeutic approaches for the most aggressive epithelial thyroid cancers

The majority of epithelial thyroid carcinomas (TC) have a differentiated (DTC) histotype and include the papillary (PTC) and the follicular (FTC) TC which, ensuing dedifferentiation, generate the aggressive poorly differentiated (PDTC) and anaplastic (ATC) TC. Although derived from the same cell type, each TC shows specific histological features, biological behavior, and degree of differentiation because of different genetic alterations. Total thyroidectomy, followed by adjuvant therapy with 131I, is the treatment of choice for most patients affected by DTC. The prognosis of DTC patients is favorable, with 10‐year survival rate of nearly 90%. However, one third of them face the morbidity of disease recurrence and TC‐related deaths. The worst outcomes are encountered in patients with PDTC and ATC. The latter, in particular, has a mean survival time of few months from the diagnosis, which is not influenced by current anticancer treatments. Following the progress made in the comprehension of the underlying molecular mechanisms deregulated in TC progression, novel therapeutic approaches have come to light. Here, we will attempt to review new targeted therapies, which are currently being exploited in preclinical and clinical studies, with tyrosine kinase inhibitors as well as with emerging inhibitors of mitotic kinases, in PDTC and ATC.